Commonly-Used Insecticides Are Not Fully Effective Against Bedbugs

13 April 2017, 12:12 pm EDT By Anu Passary Tech Times
A study revealed that bed bugs have acquired resistance to two commonly-used insecticides. The insecticides - chlorfenapyr and bifenthrin - are not fully effective in wiping out bed bugs.  ( Justin Sullivan | Getty Images )

A new study reveals that bed bugs are developing resistance toward two most commonly-used home insecticides — bifenthrin and chlorfenapyr. This newly-grown resistance is making the insects harder to kill, forcing exterminators to use new chemicals.

The study, which was conducted by researchers from Purdue University, also revealed that apart from bifenthrin and chlorfenapyr, the bed bugs have also grown resistant to deltamethrin-based insecticides.

Resurgence Of Bedbugs

The development of bed bugs' resistance toward chemicals is being hailed as the main reason for the insect's population growth in recent times.

Cimex lectularius, the scientific name for the common bed bug, already shows major resistance toward pyrethroid-class insecticides. As a matter of fact, most of the pest control professionals — 68 percent to be exact — consider bed bugs to be one of the most difficult pests to terminate.

This is the first time researchers have conducted a study to observe bed bug resistance against chlorfenapyr, a pyrrole-class insecticide and bifenthrin, which is also a pyrethroid-class insecticide.

Bifenthrin — like deltamethrin — is a pyrethroid category insecticide, which attacks the nervous system of the bed bugs. Chlorfenapyr, on the other hand, is a chemical that attacks the insects' mitochondria of cells.

While chlorfenapyr is mainly used by professionals for pest termination, bifenthrin is also sold in shops as granules, aerosols, and insecticide sprays.

Bed Bugs: How Resistant Are They To Bifenthrin And Chlorfenapyr?

To find out the bed bugs' resistance toward bifenthrin and chlorfenapyr, researchers studied 10 populations of the insect.

The specimens were collected and provided to the researchers by pest management professionals, as well as other researchers from universities such as, New Jersey, Indiana, Virginia, Ohio, Washington DC, and Tennessee.

The researchers exposed the bed bug to the two commonly-used insecticides and measured the overall percent of bed bugs, which succumbed to death because of exposure to the chemicals within seven days.

The researchers discovered that five bed bug populations had decreased susceptibility to bifenthrin, whereas three showed resistance to chlorfenapyr. Nearly 25 percent of the bed bugs survived the exposure to the chemicals.

"Detection of reduced susceptibility suggests that certain strains may be segregating toward greater chlorfenapyr and bifenthrin resistance. These results merit continuous resistance monitoring efforts to detect chlorfenapyr and bifenthrin susceptibility shifts," noted the researchers.

The researchers shared that the study evidences that more measures need to be implemented to ward off bed bugs. One cannot rely on insecticides alone for the elimination of the pests in the long term.

"In the past, bed bugs have repeatedly shown the ability to develop resistance to products overly relied upon for their control. The findings of the current study also show similar trends in regard to chlorfenapyr and bifenthrin resistance development in bed bugs," said Ameya D. Gondhalekar, co-author of the study.

Gondhalekar thinks that further in-depth study is required to understand how bed bugs survive the exposure to these insecticides, particularly chlorfenapyr.

The study will be published in the coming week in the Journal of Economic Entomology.

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